#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int main()
{
	int i = 0;
	float sum = 0.0;
	float tem = 0.0;
	int flag = 1;
	for (i = 1; i <= 100; i++)
	{
		tem = flag * 1.0/ i;
		flag *= -1;
		sum += tem;
	}
	printf("%f", sum);
	return 0;
}